Suction type automatic swimming pool cleaners, of which there are a number of different makes on the market, are driven by water drawn to the suction side of the swimming pool filter system pump. Such systems vary in the suction pressure developed, due to differences in pump horsepower, pipe line sizes, filter capacity and condition, and other like factors.
These pool cleaners run most effectively at suction pressures somewhat less than the pressures developed by most pool filter systems. It is, therefore, desirable to reduce this pressure and to regulate the suction pressure automatically within a desired range.
This feature is particularly needed because the filter back pressure increases over time as the filter does its cleaning of the pool water. As this back pressure increases, the suction developed by the pump is lessened. This requires a valve which will maintain the suction pressure to the automatic pool cleaner at its optimum operating range. This is accomplished by bleeding less bypass water through the valve orifice. After a periodic cleaning of the filter, the suction pressure increases. Correspondingly, the valve must reduce the pump suction pressure to the automatic pool cleaner to the desired operating range (which typically is done by bleeding more bypass water).
Other suction regulating valves are presently on the market and are designed to regulate the water suction pressure for suction type automatic swimming pool cleaners. Such other valves incorporate springs, bellows, slide valves, poppet valves and other costly and complex means of pressure regulation. Examples of other such valves are the Arneson brand poppet and spring type regulating valve and the Kreepy Krauly brand bellow and spring type regulating valve. Both of these suction regulating valves are designed for use with pool filter systems and automatic swimming pool cleaners of the suction type.